This invention relates to bursting apparatus and more particularly to the separation (tearing) of a continuous web of material along transverse lines of weakening.
Forms of stationery are often preprinted on a continuous web of perforated material. Such forms are conventionally used in billing and other typical business transactions. The continuous series of forms requires processing for end use such as mailing. This may require bursting or separating the forms, as well as the performance of the end functions of stacking, stamping, sealing, inserting, collating (for additional enclosures) and folding. The aforesaid end functions are all provided for with existing equipment in one continuous process. There is, however, need for an inexpensive apparatus that performs a separating function and that can be integrated with existing paper handling equipment. The present invention fulfills this need by using a novel principle of operation as hereinafter described in detail.
U.S. Pat. No. 704,472 teaches the use of two pairs of rollers driven at different relative speeds to effect sufficient tension on perforated paper directed between them to cause separation. Apparatus of that general class often require two distinct means for driving pairs of rollers at different rates of speed, complex gear or pulley systems for effectuating different roller surface velocities derived from the same drive means, or rollers with different radii each of which systems entails its own special set of problems, not the least of which is cost due to complexity.
U.S. Pat. No. 773,816 teaches the use of a braking mechanism in a ticket dispensing system to halt infeed rollers without affecting the outfeed rollers. The braking mechanism in that system consists of a cam mounted on a shaft which forces a flap against a spring-assisted lever at predetermined intervals. Besides the eventual inoperativeness of that system due to component misadjustment and fatigue, that system suffers from the following drawback: tickets of only one length may be separated, said length being a function of the shape and circumference of the cam.
The use of a solenoid clutch in combination with a clamping bar is taught in U.S. Pat. No. 3,888,399, assigned to the present assignee. A segmented burster roller is rotated once per cycle, each time a continuous series of forms is advanced to a predetermined bursting position. Drive to the infeed rollers is disengaged after each cycle to allow the burster roller to separate a form from the continuous series of forms. A timing cam ensures disengagement of the infeed rollers and rotation of the burster roller at the proper time, as predetermined by the form length in that system. A method of bursting without recourse to intermittent advancement techniques, however, is thought to represent an improvement in the burster art by using less moving parts and thus extending the life of the mechanism.